J frame repair

[rayi1958]

Hi I'm looking for some help/advice please my 26 J frame has a broken upper rear leg between the seat post and rear axle plate, I want to replace the tube (replace both upper legs the other leg has been poorly welded at some time) rather than just welding the break my question is how to go about removing the frame tubes, is it possible to heat where the tube is brazed to the axle plate and basically pull the joint apart ? I realize I need to sweet / heat both top and bottom tubes and completely remove the axle plate to replace the top tube but are these joints (tube to castings) pinned as well as brazed ? my trade is welder / steel fabrication so I feel confident that I have the skills and equipment to do the work but I've never attempted to separate frame tubes from castings before any advice would be much appreciated thanks regards Ray

[exeric]

I believe J frames are either double, or triple butted at the axel carriers, and seat post forging. Also, H-D pinned the tubes to the forgings so that complicates the disassembly. I think it would be very difficult to sweat those tubes out without contaminating the forging but you would know more about that than I would. I've machined tubes out of forgings and that works well, but getting a forging into a mill vise means you'll will have a major frame fabricating job, and fixtures to build. . . . Sorry, not very good news so far. However, if you do want to replace all the tubes you'll need to make a frame fixture and very carefully document what you have. J frames are off-set on the left side for sprocket clearance so left, and right tubing is not symmetrical. I had to re-build, and re-tube the rear section on my 1916 J frame. I recall that I left some joints intact and made a tubing splice and that was a judgement call on my part. I know this just scratches the surface of what is involved but it sounds like you know your way around, Ray. It comes down to a good surface plate, fixturing, and endless measurements.

[Jerry Wieland]

If I cannot get the frame piece in a mill I cut the tube and then dremel the tube in a couple of places inside the casting and then 'peel' it out of there with heat and a chisel. Slow and easy - not the place to get in a hurry or use too much heat. Make sure you know where the frame stay needs to be before assembly. Sometimes I build fixtures before I start the removal process. Jerry

[rayi1958]

Thank you Eric exactly the sort of advice and knowledge I was hoping for people who know these bikes inside and out , I'm glad I asked before tearing in with the oxy acetylene torch in hand haha I'm now thinking possibly replace some of the rear leg with a splice joint, the rest of the frame is very decent so defiantly worth the effort , thanks again Eric much appreciated cheers Ray

[rayi1958]

Thank you also Jerry same as the above reply to Eric your knowledge and experience is invaluable I don't think I'll be trying to sweat anything apart it will be cut dremel and chisel, I really appreciate the advice and sharing your experience cheers Ray

[gharper]

I've had very good luck "unbrazing" frame fittings, on Excelsior frames and handlebars anyway. These tubes are always pinned into the fitting and sweat brazed. Clean the entire fitting off by either blasting or wire wheeling. Look closely and you can find the pin, IF the metal is clean! Drill out the pin from both sides and then it will come apart easily if you're careful with the heat: just enough to get the bronze to flow and pull / twist it apart, like unsoldering copper pipe. Once cooled you will need to deburr the ID of the casting to fit the new tube, make sure it is perfectly clean! For final assembly, lots of Flux in the hole and on the tube and then pin the tube again, using the original hole in the casting then braze it up. It also helps to get a high grade brazing rod which is much stronger than the standard "yellow solder" as Howard Wagner used to say! Also be sure there is a tiny vent hole in every tube. This is usually drilled on the underside of the tube. It will allow pressure to vent out during the brazing process, otherwise it may want to push out the flux and or brazing material. This pin hole can be filled after the main brazing area cools if you can't live with it! Good luck, and easy on the heat!

[T. Cotten]

I've had very good luck "unbrazing" frame fittings,...

Me too, Gene!

Mostly.

Here's how Indian handlebars were pinned similarly.

PINNED1.jpg

pinned2.jpg

For fillers, I always chose a silver solder of the same melting temperature or lower, if I could.

....Cotten

[rayi1958]

Thanks for the input gharper it's much appreciated and encouraging I'll give it a go cheers Ray

[meoracing.ca]

Well, how did it go rayi1958 ?

I am curious to know.